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The cooperative relaxation dynamics of methylene units in self-assembled amorphous alkyl nanodomains with typical dimensions in the range 5–20 Å is studied in a series of poly(1,4-phenylene-2,5-n-dialkyloxy terephthalate)s (PPAOTs) with C = 6–12 alkyl carbons per side chain. These comb-like polymers are long range ordered on the nanoscale since domains where main chains are stacked in a crystal-like...
This study investigated the role of polybutadiene-g-polypentafluorostyrene (PB-g-PPFS) as a coupling agent between lignin and styrene butadiene rubber (SBR) in preparation of compounds with higher mechanical strength and lower viscoelastic loss. Lignins are three-dimensional amorphous polymers consisting of benzene rings carrying alkyl, alkoxy, and hydroxyl groups as substituents. These substituents...
Nanoparticles with a multi-domain structure have been identified as a new class of highly potent nanocarriers with a dual transport mechanism for polar and non-polar guests. In this paper we present a detailed analysis of their spatial structure, which has been analyzed by small-angle neutron scattering (SANS) including contrast variation. The nanocarriers consist of a hyperbranched polyglycerol (hPG)...
Poly(diphenylacetylene) [PDPA] derivatives were nitrated using a mixture of nitric acid and sulfuric acid. Nitration of poly[1-(p-trimethylsilyl)phenyl-2-phenylacetylene] (1a) proceeded, and the nitro groups were substituted to trimethylsilyl groups on benzene rings. The degree of nitration (DN) increased with reaction time, and it reached 0.41 for 3.0 h. Fluorine-containing PDPA (1b and 1c) showed...
We propose an integral procedure to simultaneously obtain the three Flory–Huggins interaction parameters in polymer(3)/solvent(2)/nonsolvent(1) systems by carrying out only viscosity and cloud point measurements. First, the interaction parameter between polymer and solvent, χ23, is obtained by applying the Rudin's model which has been well established for various polymer solutions. Then the solvent/nonsolvent...
Differential fast scanning calorimetry (DFSC) was employed on poly(butylene succinate) nanocomposites containing silver nanoparticles and multi-walled carbon nanotubes (MWCNT), in order to identify the temperature range of heterogeneous nucleation caused by both nanofillers. The fast scanning rates also allow investigating self-nucleation by recrystallization experiments approaching the crystallization...
To improve the form-stability and lower the degradation rate of poly(trimethylene carbonate) (PTMC) in biomedical fields, the cross-linked PTMC networks (PTMC-Ns) with controllable properties were prepared via chemical cross-linking. We report higher gel percentage and lower swelling degree as well as enhanced thermal and mechanical properties of the PTMC-Ns by increasing the initial molecular weight...
While aromatic diglycidyl ether of bisphenol A (DGEBA) based epoxy polymer matrix systems are important for high-performance applications, their brittle nature is an issue that needs to be addressed. In this paper the authors show that small additions of a more flexible aliphatic epoxy copolymers, both di- and tri-functional, can significantly increase the notched Izod impact strength (56–77%) over...
Double emulsion templates made by microfluidics allow for the production of tailored and monodisperse microcapsules. However, their mechanical properties cannot be predicted by traditional analytical models because of their relatively thick shells. In this work, we produce thick-shelled microcapsules with varying sizes and shell thicknesses and mechanically characterize them in single-capsule compression...
The performance of semicrystalline polymers is significantly dependent on the crystal morphology and lamellae orientation. In this work, the crystal superstructure and mechanical properties of polylactide (PLA) with different amounts of nucleating agent (tetramethylene-dicarboxylic dibenzoyl-hydrazide, TMC-306) were investigated. It was found that TMC-306 can be dissolved in PLA melt and re-crystallize...
Carbon nanotube (CNT) can exhibit electrical conductivity and introduce electric current into polymer. Using dry-jet-wet spin technology, polyacrylonitrile (PAN)/CNT composite fibers with 15 wt% and 20 wt% of CNT content were fabricated. The electrical conductivity of PAN/CNT fibers was enhanced by the annealing process at different temperatures and changed with time. These fibers could also respond...
Equilibrium water sorption properties of amorphous poly(ethylene furanoate) (PEF) and amorphous poly(ethylene terephthalate) (PET) were studied at 35 °C over the entire water activity range. PEF exhibits a largely increased equilibrium water sorption capacity of ∼1.8× averaged over the entire concentration range compared to PET, resulting from substitution of the non-polar phenyl ring in PET with...
We use Positron Annihilation Lifetime Spectroscopy (PALS) in conjunction with calorimetric measurements to investigate the effects of two polyols (sorbitol and glycerol) and water on the molecular packing and thermodynamic state of low water content gelatin matrices. Our calorimetric measurements show that water, sorbitol and glycerol all reduce the glass transition and dissociation/denaturation temperatures...
Thermoplastic elastomer nanocomposites based on acrylonitrile butadiene rubber (NBR) and poly(ethylene-co-vinyl acetate) (EVA) with different weight ratios (20, 40 and 60 wt% of NBR) and 5 wt% of organocaly (OC) were prepared in an internal mixer. The results obtained from X-ray diffraction and transmission electron microscopy (TEM) micrographs showed that due to the OC–EVA interaction, nearly all...
Reacting ortho-functional poly(hydroxyimide)s via a high-temperature (i.e., 350 °C–450 °C) solid-state reaction produces polymers with exceptional gas separation properties for separations such as CO2/CH4, CO2/N2, and H2/CH4. However, these reactions render these so-called thermally rearranged (TR) polymers insoluble in common solvents, which prevent the use of certain experimental characterization...
The interfacial interaction of composites dominates the properties of polymeric/inorganic nanocomposites. Herein, epoxy and hydroxyl groups are introduced into the natural rubber (NR) molecular chains to anchor oxygenous functional groups on the surface of graphene oxide (GO) sheets and therefore enhance the interfacial interaction between GO and rubber. From the morphological observation and interaction...
Novel biodegradable nanocomposite blown films based on compatibilized poly(lactic acid)-poly(butylene adipate-co-terephthalate) blend are fabricated for use as a model package for dried longan. Silver-loaded kaolinite (AgKT) dispersing in the polymer matrix in intercalated-exfoliated fashion functions as an excellent property improver of the blend. The emphasis of this paper is enhancement of film...
Two naphthalimide derivatives (DMAENs) containing tertiary amine groups have been designed and synthesized. Upon exposure to near UV and visible LEDs (365 nm–455 nm), they lead to radicals without adding a hydrogen donor and, in combination with 2,4,6-tris(trichloromethyl)-1,3,5-triazine, an iodonium salt or N-vinylcarbazole, they produce radicals and cations. Compared to the well-known camphorquinone...
Microinjection-molded and compression-molded polyamide (PA12) matrix composites filled with 0.67, 1.33, 2 and 4 wt% multi-walled carbon nanotubes (MWNTs) were prepared from twin-screw extruded pellets. The compression molded samples have an electrical percolation threshold close to 1.2 wt%. Coupled rheological and electrical measurements show that their electrical properties start decreasing as soon...
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